1. Field of the Invention
The present invention relates to a programming system for introducing the program into an accounting, calculating or other office machine which performs data-processing operations, wherein the instructions of the program are represented by a series of coded storage elements disposed around the periphery of a circular carrier, which may be referred to as a drum, and comprising a reading unit for reading the storage elements and a feed mechanism adapted to be actuated to cause the carrier to rotate with respect to the reading unit.
In programmable office machines having an internal memory of small capacity there is the need to introduce the instructions of the working program of the machine from time to time. These programs are normally stored permanently on readily handleable carriers or recording media such that the recorded instructions do not suffer impairment owing to prolonged use of the carrier or recording medium.
2. Description of the Prior Art
It is known to use a magnetic card, a magnetic tape or a punched card as recording carrier or medium. Generally, however, while these are inexpensive and readily handleable carriers, they require rather complicated and costly reading devices which have a considerable effect on the total cost of the machine to which they are applied.
A calculating machine having a movable carriage is also known which employs for introduction of the program instructions a drum arranged inside the machine and which bears round its periphery a plurality of lamellae or plates provided with a series of teeth which carry working instructions stored in coded form. The cylinder is rotated in conjunction with the movement of the carriage and the various plates are read one after the other by a series of sensing levers to execute the working instructions represented by the combinations of the teeth.
This system requires simple reading means of low cost and which can supply information which can be executed without lengthy conversion operations; on the other hand, since the drum is mounted inside the machine and is an integral part thereof, replacement thereof cannot be carried out directly by the operator, but only by technicians equipped with suitable tools. Consequently, the services performed by the machine are limited in practice to the single program built into the machine.